The invention relates to a semiconducor device for the vacuum-emission of electrons through one of the surfaces of said semiconductor device.
Such semiconductor devices may be, for example, photocathodes which are used in camera tubes or photomultipliers. Such photocathodes ensure a conversion of photons into electrons. The semiconductor devices, however, may also be dynodes which are used in photomultipliers which operate with secondary electron emission.
Electron emitter devices which generally operate in a vacuum are known from U.S. Pat. No. 3,959,038 both as regards their structure and their manufacturing process. This specification describes photocathodes of GaAs which operate in transmission, which means that photons enter on one side and electrons emanate on the other side.
These devices comprise an active layer which adjoins the emitter surface and in which at least three physical processes occur. The first process is the excitation of an electron, for example, under the influence of radiation (light) in the case of the photocathodes. The second process is the diffusion of said electron in the active layer. The third process is the emission into a vacuum of an electron. These three different physical processes are based on different physical laws and depend on other parameters.